FORMATION OF METALLIC COATING OF DIELECTRIC CORE

PURPOSE:To stabilize a resonance frequency and to improve yield by forming lands at respective side parts of a dielectric core and near the hollow part. CONSTITUTION:The entire surface of the dielectric core 11 having the columnar hollow part is plated with copper by an electroless plating method to form a copper coating. Then, the film is masked with resist ink. Then, electrolytic silver plating is carried out to connect an internal conductor 13 to an external conductor 14 and masking is performed so that lands 17 and 18 are formed of a silver- plating coating. A thickness coating of silver is formed by electrolytic silver plating after the resist ink is dried, and the internal conductor 13, external conductors 14 and 15, an excitation pattern 16, and lands 17 and 18 are formed. Then, the resist ink is dissolved to etch away an unnecessary copper coating. Therefore, the internal and external conductors and lands are formed at the same time, so the positioning in resist printing is facilitated to improve the productivity. Further, the lands are formed to prevent a defect of the coating.